Alistar Vs Thresh

alistar 40% cdr has 8 and 6 sec cd on his Q and W making his adc really safe

This may sound cliché, but its situational. You will have to play both champs and get a feel for them. They are both super good for different situations.

You have played the game long enough to understand that no 2 champions feel the same, right? Well, comparing Alistar to Thresh is doing that. You will have to look at the team comp you have, and decide off that.

For example, Orianna works amazing with Alirstar, that is a 10/10 engage, 3-4 man knock-up, with orianna ult? GG!

Thresh, is a good counter to Jarven because he can Flay his E+Q combo, 10/10 peel.

I think Alistar is better at pealing but Thresh is better at teamfights.